Which injector o-ring is bad?

[racnruss]

Is there any way to tell which injector has a bad o-ring causing oil consumption without pulling all the injectors?

[RT]

If you pull your valve covers, and run the truck, you will see oil spilling up around the injector that is bad. There is a oil deflector over the area where oil is supposed to come up, but the bad one may have oil coming from different areas.

In my opinion - if you have the valve cover off - and if you already have one going out - you might as well change them all or you'll just be putting off the inevitable.

[racnruss]

thanks for the information. Truck is my brother in law's and he just recently replaced all the o-rings with Alliant power rings. That's why we just want to pull the bad one.

[klhansen]

You can narrow it down to either right or left bank by blocking the HPOP hose to one of the heads and monitoring HP oil pressure with either a scan tool or a gauge (0-3000 psi). The one with the leak will be lower, or show a higher IPR duty cycle. If it's causing oil consumption it would be the the middle o-ring between the oil and fuel rails. The only way you could see the leak by pulling off the valve covers is if the top oil o-ring is leaking. If the top o-ring is OK, but the middle o-ring is GONE, you still wouldn't see anything coming up around the injector.

Are you seeing oil in the fuel filter bowl? The higher pressure in the fuel rail caused by the leak will cause oil to back up into the bowl. You might be able to identify it by pulling the fuel lines feeding the heads and inspecting the contents for higher oil content on one side, although if it's getting back to the filter bowl, it'll probably be mixed and sending pretty much the same mixture to both heads.